Closure cap with snap hinge and retaining ring

ABSTRACT

The present invention concerns a closure ( 10 ) consisting of a cap portion ( 1 ), a retaining ring ( 3 ), a tear strip and a snap hinge ( 20 ), the snap hinge connecting the cap portion and the retaining ring in a single piece along a first circumferential section, wherein the cap portion ( 1 ) has a top plate ( 14 ) and the closure having overall a substantially cylindrical or slightly tapered closure skirt which, inter alia, comprises a substantially cylindrical cap skirt and the retaining ring ( 3 ), wherein the snap hinge ( 20 ) is integrated into the skirt and wherein the retaining ring ( 3 ) and the cap portion ( 1 ), in addition to being connected via the snap hinge ( 20 ), are also connected together along a second circumferential section ( 30 ) via the tear strip ( 4 ) which is also integrated into the skirt. To produce such a closure but at low cost and preferably using only a little material, and in particular to provide improved protection of the inside of the closure against environmental influences, the invention proposes that the cap skirt, tear strip, snap hinge and retaining ring together define an essentially closed closure skirt wherein the tear strip and the ends of the snap hinge ( 20 ) in the circumferential direction are connected with the cap skirt and/or the retaining ring and optionally with one another via film-like, easily tearable lines of weakness.

The present invention relates to a closure consisting of a cap portion, a retaining ring, a tear strip and a snap hinge, the snap hinge connecting the cap portion and the retaining ring in a single piece along a first circumferential section, wherein the cap portion has a top plate and the closure having overall a substantially cylindrical or slightly tapered closure skirt which, inter alia, comprises a substantially cylindrical cap skirt and the retaining ring, wherein the snap hinge is integrated into the skirt and wherein the retaining ring and the cap portion, in addition to being connected via the snap hinge, are also connected along a second circumferential section beyond the sector associated with the snap hinge via the tear strip which is also integrated into the skirt.

A plastic closure of the above type is known from WO03/057585 A2. It defines therein a snap hinge as a hinge which, in addition to the closed position of the closure cap, also has a stable open position. Such a snap hinge is in that case formed as a single piece with the cap and the retaining ring. The particular feature of a snap hinge, of the type on which the present invention is based, is that the snap hinge is integrated into a substantially cylindrical skirt wall of the closure cap, i.e. forms part of said substantially cylindrical skirt wall. This skirt wall can also be slightly tapered or convex and in particular can be provided with gaps and fine structures, for example in the form of lines of weakness, which define the borders or film hinges between the individual components (cap, tear strip, hinge, retaining ring) of the closure.

Prior art snap hinges were added onto the outside of a first wall of the closure so that in the region of the snap hinge the closures were in effect double-walled, whereas the hinge of the closure on which the present invention is based is integrated into the wall formed by the cap skirt and the retaining ring. This allows the cap to be manufactured in a single piece in the closed state, ready for application or ready for se. In contrast, prior art closures with snap hinges have to be manufactured in an open, deployed condition, which makes integral manufacture with the tear strip almost impossible.

Here, the cap skirt and the retaining ring do not necessarily have to have a circular cross section, but can have any circular, elliptical or polygonal cross section. The snap hinge effect is achieved by at least one or more thin, flexible and substantially linear wall sections of this hinge running essentially in the circumferential direction, onto which bulky and stable wall sections connect. Appropriate shaping can give the hinge a “dead-point” property, i.e. on opening of the cap, the hinge resists the motion of opening and deploying to a certain extent, but after going beyond the dead-point, switches into a state in which the elastic energy operating in and on the hinge impels the closure cap into an open, deployed position. This “dead-point” property, i.e. at least one labile position of the cap between at least two stable positions which preferably define the closed and the completely open state, whereby the cap, starting from a first stable position, when moving through the dead-point “snaps” into a second stable position, is the characteristic feature of a snap hinge—whence the expression “snap hinge”.

The retaining ring retains the entire closure on the neck of a container, for example a bottle. The bottle neck is usually provided with a circular circumferential retaining flange. In the initial closed position, the retaining ring grips the bottle neck behind the retaining flange and thus securely retains the closure on the bottle neck. To this end, the retaining ring preferably has a circumferential inner circular bead which grips behind the retaining flange. Thus, the tamper-proof strip connecting the closure cap and the retaining ring has a security or tamper-proofing function as it connects the closure cap and the retaining ring attached to the neck of the bottle along a circumferential sector beyond the snap hinge so that the closure cap can only be opened after the tamper-proof strip has been removed, i.e. after the connection of the tamper-proof strip to the cap and the retaining ring has been destroyed. After removing or tearing off said tear strip, the only remaining connection between the retaining ring and the closure cap is the snap hinge and the cap can be opened, whereupon it is pivoted upwardly and outwardly relative to the retaining ring about the snap hinge which extends over a specific small sector of the closure skirt.

An inner bung or circular sealing web can also be provided, with an external diameter which is slightly larger than the internal diameter of the neck of the bottle, so that the closed cap grips the inside of the neck of the container and thus seals the contents from its surroundings.

In the known closure, the snap hinge extends over a first sector of the circumference of the cap and retaining ring and the tear strip extends over most of the remaining sector, in or parallel to a plane of the closure inclined at less than 90° to the axis of the closure, and thus is at a certain distance from the sector of the snap hinge, so that between the ends of the tear strip (seen in the circumferential direction) and the ends of the snap hinge there are openings in the skirt of the closure. This requires that the closure has a certain axial length and the open regions between the tear strip and the snap hinge can lead to the ingress of dirt, dust, germs and small animals or insects under the closure cap, so that the mouth of the bottle neck could become dirty or even contaminated, even though the closure is completely closed and the tamper-proof strip is intact.

Further, because of the inclination to a perpendicular to the closure axis of the tamper-proof strip in this known closure, it has an axial length which is larger than the sum total of the minimum (axial) widths of the cap skirt, the tamper-proof strip and the retaining ring.

Having regard to this prior art, the aim of the present invention is to provide a closure with the features defined above which, however, can be manufactured at low cost and preferably only requires a little material, and which above all can better protect the inside of the closure from external influences.

This aim is achieved by dint of the fact that the cap skirt, tear strip, snap hinge and retaining ring together define an essentially closed closure skirt wherein the tear strip and the ends of the snap hinge in the circumferential direction are connected with the cap skirt and/or the retaining ring and optionally with one another via film-like, easily tearable lines of weakness.

This means that in the closure of the invention, the cap skirt, the snap hinge, the tear strip and the retaining ring form a closed closure skirt around the entire circumference, as these parts are all connected together via films which are formed as a single piece with the closure and which are at least in part readily tearable. Thus, in particular, the tear strip is connected on all sides to the bordering closure elements via easily tearable films or lines of weakness in the material of the closure. Insofar as the tear strip extends only over a part of the sector of the skirt laying outside the snap hinge, then the cap or, more precisely, the cap skirt and the retaining ring are directly connected via a thin film of material which defines a tear line. Even the ends of the snap hinge in the circumferential direction of the closure are connected with the bordering portions, i.e. the tear strip or possibly (also) the cap skirt or the retaining ring, via a readily tearable film or line of weakness. In contrast, in the axial direction, the snap hinge is integrally connected with the cap portion and the retaining ring, but in a pivotable manner.

Advantageously, with a closure of the present invention, the tear strip is arranged so that starting from one end of the snap hinge and moving in the circumferential direction, it extends entirely along the remaining circumferential sector to the opposite end of the snap hinge and thus no openings or gaps remain between the ends of the tear strip and the ends of the snap hinge. This means that a completely closed skirt of the cap can be manufactured the inside of which is better protected against environmental influences.

In the preferred embodiment, the tear strip runs along the circumference of the closure skirt essentially parallel to the lower edge of the retaining ring and the top plate of the cap portion, with the exception of axial enlargements, in particular in the direction of the cap base along shorter circumferential sectors, for example in the regions of the snap hinge bordering its ends and possibly also on the side diametrically opposite to the snap hinge. This embodiment means that an axially short closure can be produced and saves space and material when manufacturing the closure. In particular, an axially very short closure also allows a very short and thus economically produced bottle neck to be used; the amount of material saved on the neck of the bottle can be much greater than with the closure itself.

When the tear strip reaches to the snap hinge on one or both sides, then advantageously, its ends connecting to the snap hinge are so wide that they extend over the entire axial height of the snap hinge, and a tear line formed by a thin film of material connects the ends of the tear strip and the snap hinge. Since the tear strip is generally narrower (has a low axial height) than the snap hinge, it advantageously has corresponding enlargements on the ends bordering the snap hinge. Independently of such enlargements, in all cases there should be tear lines over its entire axial height along the circumferential side ends of the snap hinge, for example even when the ends of the tear strip end at a distance from the snap hinge, so that there is a space between the ends of the snap hinge and the tear strip which if necessary is filled by the cap skirt, the retaining ring or axial enlargements of these parts. These tear lines or films of material should extend to the upper end of the snap hinge and preferably to the top plate or at least very close to the top plate, and even the snap hinge itself preferably extends almost to the top plate so that overall, the closure has a very short axial height and, like the associated bottle neck, can be manufactured economically material-wise.

The recesses or axial lines of weakness bordering the snap hinge and the snap hinge thus preferably extend into axial regions which are otherwise taken up by the cap skirt, which itself must have a sufficient axial height over at least a portion of the circumference in order to be able to grip a bottle neck. This minimum axial height of the cap skirt should not be less than 2 mm and is preferably at least 3, more preferably at least 4 mm measured from the exterior of the top plate. Thus the expression “extends almost to the top plate” for the recesses and the snap hinge means that the corresponding parts replace or do away with a part of the cap skirt.

In a preferred embodiment, the tear strip is formed as a single part with at least one end of the snap hinge, preferably with both ends, via a thin film of material or a tear line, so that the tear strip can or must be separated not only from the retaining ring and the closure cap but also from the ends concerned, preferably both ends of the snap hinge.

To remove the tear strip, a tab grip is provided which, starting from one end section of the tear strip, extends radially outwardly from the closure skirt and extends in the circumferential direction over the snap hinge and is held close to the closure skirt via readily tearable webs, preferably near the snap hinge.

Such a tab grip is above all necessary when the ends of the tear strip are connected in a single piece with both opposed ends of the snap hinge, as otherwise a tool would be required to detach the tear strip. This tab of the tear hinge can, for example, be connected with the closure or with the outer side of the snap hinge on the closure via readily frangible webs.

The inventive closure ensures that the interior of the closure is completely closed to its external surroundings prior to the first use. This is particularly the case when the tear strip is connected with the retaining ring and the closure cap as well as at its end portion with the end portion of the retaining hinge via a thin, readily tearable film of material instead, as is known in principle in the prior art in other cases, by a plurality of readily frangible connecting webs between which a gap is left which could constitute an opening between the outside and the interior of the closure. Further, part of the films of material connecting the individual closure elements could if necessary be replaced by a gap bridged by readily tearable connecting webs namely, for example, at the connection between the retaining ring and the tear strip when the tear strip is close to the neck of a container or neck of a closure, or possibly also at the end portion of the snap hinge, where a connecting web could be dispensed with, in particular when the elements bordering the gap lie very close to each other, preferably in contact with each other.

Such a closure can also be produced cheaply as at least in its simplest variations it can be produced using two relatively simple tools which only have to be pushed together axially, even when complex embodiments and tools are brought in for some applications. The cap skirt, the tear strip and the retaining ring form a continuous cylindrical, slightly tapered or stepwise slightly broadening opening wall going from the cap skirt to the retaining ring. As an example, the cap skirt may have an external diameter of approximately 36.5 mm, while the retaining ring has a slightly larger external diameter of 39.5 mm, for example, whereby the tear strip and also the snap hinge together form a tapered transition from the cap skirt to the retaining ring. Small undercuts, for example on the lower inner rim of the cap skirt, on the lower inner rim of the retaining ring and also forming lines of weakness or film hinges on the snap hinge, can be produced without the need for multi-part inner moulds and can be worked directly into the inner mandrel as long as these structures only have a small radial depth of less than 1 mm, for example. The closure is then, for example, produced by injection into a two-part mould which consists of an outer mould and an inner mandrel, wherein the outside has no significant structures and thus the outer mould can easily be removed from the closure because of the light undercuts on the inner mandrel. After the outer mould has been removed, the inner mandrel can easily be separated from the closure as the regions which are axially below the undercuts easily expand in a reversible manner during unmoulding due to the elasticity of the materials usually employed for the closure.

If in addition the tear strip also has a tab grip extending parallel to the outer skirt or to the snap hinge of the closure, then clearly the mould must be supplemented by the corresponding mould elements which, however, do not cause any major overcasts and again if necessary can make use of a relatively simple two-part injection moulding tool.

In the preferred embodiment of the invention, the tear strip is also formed so that in its regions bordering the snap hinge it also approaches the top plate or close to the top plate, i.e. in this region forms part of the cap skirt, while the tear strip is still present. Advantageously, the two ends of the tear strip bordering the snap hinge are enlarged in the axial direction up to the top plate, for example over a length of 2 to 6 mm in the circumferential direction, while the upper axial border of the tear strip, i.e. the line of weakness formed between the tear strip and the cap skirt, then moves away from the top plate and in the remaining region of the second sector is at a distance of 1 to 5 mm, for example, parallel to the top plate in the direction of the circumferential direction. This distance from the top plate the line of weakness between the tear strip and the cap thus corresponds to the remaining axial length of the cap skirt. As a result, in both regions bordering the circumferential ends of the snap hinge, the cap skirt runs close to the top plate and is replaced by the enlargements of the tear strip. This is of particular advantage when the snap hinge is essentially adjacent to the top plate.

Examples of essential parts of a snap hinge are two film-like, readily bendable connection lines formed from rather thinner material which is also defined as a “film hinge” and connects the bordering relatively stiff and thicker sections of the hinge material together which run essentially in the circumferential direction, but also have axial components so that in the approximate centre of the snap hinge they are fairly close together and then diverge (in the axial direction) towards the ends of the snap hinge in the circumferential direction. The (three) thicker and stiff sections of the snap hinge lie between the two film hinges or connect over the upper and under the lower film hinge.

The profile of the upper film hinge corresponds, for example, to the section of a cylindrical skirt surface with a plane inclined to the cylindrical axis and thus lies along a circular or, more precisely, an elliptical curve in a plane inclined to the top plate with the centre of the curve above the top plate as the two ends of this curved film hinge lie closer to the top plate. The lower film hinge thus, for example, also follows an elliptical curve which also runs in a plane which is inclined to the top plate, however it has a centre which is substantially below the top plate and, for example, also below the retaining ring, so that the ends of the lower film hinge extend away from the top plate towards the retaining ring. The total axial height of the snap hinge is essentially determined by the distance between the film hinges which diverge from one another towards the ends of the snap hinge. This distance clearly also depends on the width (in the circumferential direction) of the film hinge and on the diameter of the closure, but in a typical closure with a diameter of 35 to 40 mm is approximately 5 mm.

The measures described above, such as the snap hinge extending up to the vicinity of the top plate and the tear strip also extending in some sectors close to the top plate, allow such a closure to be manufactured with a very small axial dimension of less than 15 mm, for example, in particular less than 12 mm, for an illustrative diameter of 35 to 40 mm. Thus, a substantial saving on material is made for the closure, and in particular on the accompanying neck of the container, even though in the unopened state, i.e. with an intact tear strip, the closure is very stable and tight when in accordance with the preferred embodiment the cap skirt, tear strip, snap hinge and retaining ring define a continuous cylindrical or tapered or part-tapered skirt of the closure with no gaps or breaks.

The function of the snap hinge can be described as follows. The snap hinge consists, from top to bottom, of a section bordering the top plate which has approximately the shape of a circular section. The outer rim of this section is defined by a curved upper film hinge. Connected to this is a somewhat more stable hinge section which in turn is bordered lower down by another curved film hinge with an opposed curvature. In side view, this stable part of the snap hinge thus has approximately the shape of a flattened “X” with curved arms.

At the same time, in a top view the snap hinge is also curved in a radial plane, i.e. it forms part of a cylindrical (or slightly tapered) skirt of the closure.

This means that when lifting the closure cap, i.e. on opening the closure, after removing the tear strip, the initial effective rotational axis about which the closure cap pivots, in the approximate region of a tangent to the middle section of the hinge, actually lies within the upper film hinge and in the central region thereof. The top plate and the circular sectional-shaped portion of the cap skirt bordering the film hinge essentially move rigidly as a unit about this axis. This necessarily means that both ends of the film hinge, which are at a distance from the effective initial pivotal axis, are stretched while the central region, i.e. where the two film hinges are at their closest point, tends to be compressed.

At the same time, through the rigid connection of the top plate with the circular sectional portion of the cap skirt, the central region of the hinge is pushed radially inwardly while the ends of the hinge move radially outwards. The elastic extension of the ends of the hinge and the compression of the central region of the hinge thereby produce an elastic restoring force in the closing direction.

However, as soon as the central portion of the hinge, because of its radially inward motion, and the ends of the hinge because of their radially outward motion lie in a plane, the hinge finds itself at a dead-point and further pivoting of the cap means that the outer ends of the hinge are over-centre, i.e. radially beyond the path of the effective pivotal axis which still essentially lies through the film hinge in the central region of the snap hinge and parallel to a tangent to the cap skirt in this region. The elastic tensional forces operating in the ends of the hinge then support the opening action.

Clearly, for proper function of such a snap hinge, the ends of the hinge in the region of both film hinges must be free, which in the case of the present invention means that the ends of the tear strip, which are formed in a single piece with the ends of the snap hinge, must as far as possible extend over the entire width of the snap hinge so that these ends are completely free after removing the tear strip. This saves a lot of material if as already mentioned, the snap hinge extends almost to the top plate and thus the tear strip in the present embodiment also extends almost to the top plate, or at least in the part close to the snap hinge.

In the other regions it is advantageous if the tear strip maintains a sufficient distance from the top plate to leave a corresponding skirt of the closure which on the one hand stabilizes the cap and on the other hand also has retaining properties and, for example, can have a smaller radial projection at its lower inner edge in order for it to grip behind a radially outwardly directed rim of a container opening to hold the cap securely thereon.

In a particular embodiment of the invention, however, in a region which is diametrically opposite to the snap hinge, the tear strip again approaches the top plate so that in this region too a small section of the cap skirt is separated over a length of 10 to 15 mm in the circumferential direction, for example. This recess in the cap skirt, which preferably reaches to the top plate, effectively forms a type of tab grip into which a fingertip can easily be inserted to open the cap, i.e. to remove it from the rim of the container opening.

Further, the tear strip has a constant axial width of 2 to 3 mm, for example, which only in the region near the ends of the snap hinge and in the region opposite the snap hinge is approximately doubled because there the tear strip reaches to or nearly to the top plate to ensure proper function of the snap hinge, i.e. to free the ends thereof, and also to form a tab grip on the closure cap.

In these regions, the tear strip does not have to extend right to the top plate, but may also leave a small section of the cap skirt in these regions, however with a cap skirt of only a few (for example 3-6) mm axial height, this height of the cap skirt in the regions of the tear strip mentioned above should be reduced by at least half so that the functions mentioned above are guaranteed.

In an alternative, however, a short tab grip may be formed on the cap skirt or in an extension of the top plate on the side of the cap skirt opposite the snap hinge. In this case, a recess would clearly not be required in the cap skirt in order to form a tab grip. This embodiment is preferred when used in connection with an inner retaining bead on the cap skirt which will be described below.

Where the cap skirt is at its maximum height, i.e. essentially beyond the snap hinge and the bordering recesses in the cap skirt, the cap skirt has an inwardly projecting bead or seam near its lower edge which can snap behind a corresponding projection at the mouth of a bottle neck or the like.

Preferably, the radial thickness of the bead is at its maximum only in the region opposite the hinge where the tab grip may be located. The circumferential section along which the bead is of maximum radial thickness preferably corresponds to no more than 120°, more preferably no more than 90° and in particular at most 60°, wherein the centre of this section lies diametrically opposite the centre of the snap hinge. Particularly preferably, the thickness of the bead, starting from a maximum value in a small central section or point, reduces continuously and by at most about 90° either side of the central point either runs out or reaches its minimum thickness.

This embodiment has the advantage of providing a better and more secure seal of the closure when closing it again. The consumer who has grasped the closure on the side opposite the snap hinge, possibly by a tab grip and has opened it and now wishes to close the closure again typically will grip only the part of the closure cap which is close to the tab grip or the part diametrically opposite the hinge and press this side of the closure cap from above onto the associated bottle neck or container neck to which the closure is attached. As already mentioned, the upper edge of this bottle neck, which is designed for attachment of an associated closure, carries an outwardly projecting retaining bead. On pressing down on the closure cap, the inwardly projecting bead on the cap skirt slides over the outwardly projecting bead on the edge of the bottle neck and snaps behind it. However, if the inwardly projecting bead were to extend over the entire circumference of the cap skirt or along a circumferential sector of more than 180° centred on the central point opposite the snap hinge, but pressure is exerted from above on the top plate or tab grip only in the region of this central point or in the region of the tab grip, the bead of the cap skirt in the region of the tab grip may indeed slide over the retaining bead of the edge of the bottle neck but in the remaining regions, especially those at about 90° to the centre of the tab grip, it may sit on the retaining bead of the edge of the bottle neck without sliding over it. The closure would then bulge in the middle between the hinge and tab grip and this deformation of the closure cap could no longer guarantee a tight seal on closing. Hence, in the preferred embodiment of the invention, the inwardly projecting bead on the skirt of the closure cap only reaches its maximum thickness in a section near the tab grip, i.e. diametrically opposite the hinge, and diminishes with increasing distance from this central region and preferably has reached a minimal value by 90° from the central region and may completely disappear, the whole circumference of the closure cap and the base of the cap dropping onto the rim of the bottle neck even when pressure is only exerted from above on the cap portion in the region of the tab grip. In this manner a smaller radially inwardly projecting bead which is at a distance from the tab grip will slide over the bead on the edge of the bottle neck with a lower resistance so that it does not result in a bulge in the closure cap in the central region between the hinge and the tab grip.

Further, a ring-shaped sealing web is advantageously provided on the top plate which is dimensioned so that it extends into the interior of a bottle neck or container opening and thus acts as a bung; advantageously it has a beadlike projection along its outer circumference which acts as a seal on the inner surface of a corresponding bottle neck, but it must have an exterior diameter which is slightly larger than the internal diameter of the corresponding bottle neck or opening.

In one embodiment, the closure is manufactured for a bottle neck with an internal diameter of 33 mm and an external diameter of 35 mm wherein, as already mentioned, the external diameter of the internal sealing web in the region of the bead is correspondingly slightly larger than 33 mm, for example 33.5 mm and the inner edge of the (not totally circumferential) cap skirt has an internal diameter of 35.5 mm, for example.

For the purposes of original disclosure, it should be noted that any features of which a skilled person becomes aware from the present description, drawings and claims, even if they are only specifically described in connection with particular further features, can be combined both individually and in any combinations with other features or combinations of features disclosed herein, insofar as this is not expressly excluded or such combinations are impossible or of no purpose for technical reasons. A comprehensive explicit description of all envisageable combinations of features has not been given here purely for the purposes of legibility of the description.

Further advantages, features and applications of the present invention will become apparent from the following description of a preferred embodiment made with reference to the accompanying drawings, in which:

FIG. 1 shows a side view of an embodiment of a closure applied to a container neck;

FIG. 2 shows a side view of a closure according to claim 1 seen from the side of the snap hinge and without a tab grip for the tear strip;

FIG. 2 a shows a section through the closure of FIG. 1 along the plane D-D in FIG. 4;

FIG. 3 shows a side view corresponding to FIG. 2, but with the tab grip of the tear strip which partially conceals the snap hinge, and wherein the left side of the closure is shown in section;

FIG. 4 shows an axial sectional view along plane C-C in FIG. 1;

FIG. 5 shows an axial view of the closure from above;

FIG. 6 shows a side view through the closure applied to the neck of the bottle;

FIG. 7 shows a detail of the side view of FIG. 6;

FIG. 8 shows a further detail of the side view of FIG. 6; and

FIG. 9 shows a further detail of circle E in FIG. 2 a.

FIGS. 1 to 6 show a closure which is generally denoted 10 which consists of a closure cap 1, a retaining ring 3 and a tear strip 4 arranged between the closure cap 1 and retaining ring 3. The tear strip 4 connects the retaining ring 3 and the closure cap 1 via a line of weakness denoted 15 to 19. The lines of weakness 15, 19 consist of film-like thinned linear or strip shaped sections of the closure skirt. As can be seen, the closure widens from top to bottom, particularly in the region of the tear strip 4, in a somewhat stepwise manner; the cap skirt 2, the tear strip 4 and the retaining ring 3 are essentially cylindrical. The retaining ring 3, which has a somewhat smaller internal diameter than a radially outwardly projecting retaining flange 32 of the bottle neck 30 (see FIGS. 3, 6, 7 and 8), grips behind this flange 32 and thus retains the closure 10 as a whole on the radially outwardly projecting flange 32 or projection of a bottle neck 30 or a connection opening.

A ring-shaped circumferential sealing web 18 (see FIGS. 2 a and 3) extends from the top plate 14; at its outer circumference it has a small circumferential bead which extends into a corresponding bottle neck 30 as a sealing bead when the closure is put on to the bottle neck and the cap 1 is closed.

The lower rim of the cap skirt 2 also has a small inwardly directed projection 12 (FIG. 7) which can grip behind an outwardly bulged snap rim 33 of the bottle neck 30 to retain the cap 1 in the closed state securely on a container opening, even when the tear strip 4 is removed and the cap is only connected with the retaining ring 3 via the snap hinge 20.

FIG. 3 shows an external view of the closure in the region of the snap hinge, in FIG. 3 partially covered by the tab grip 13 of the tear strip 4, wherein two lines of weakness or film hinges 6, 7 with the section 8 lying therebetween and the upper and lower connected sections 16, 17 illustrated by curved dotted lines form the snap hinge 20. As can be seen, these film hinges 6, 7 are curved so that in approximately the centre of the hinge 20 they are at a small distance from each other and diverge outwardly towards the ends of the hinge. Between these two film hinges 6, 7 is a rather larger web 8 which is tapered in the centre and widens towards its two ends, while the film hinge on the other side is delimited by a curved widened section 17 of the retaining ring 3 and a curved portion 16 of the cap skirt 2, additionally reinforced by a substantially rectangular base 9, which contribute to the snap function of the hinge 20 insofar as they form a relatively stiff connection of the hinge with the retaining ring 3. The right and left hand ends 21, 22 of the snap hinge 20 are defined by thin film-like and easily tearable connections to the bordering sections of the tear strip 4 which has axial enlargements 5 at its sections bordering the ends 21, 22 which occupy corresponding recesses 25 in the cap skirt. To avoid tearing the relatively thin walled film hinge 6, 7 of the snap hinge from the ends 21, 22, both sides of the snap hinge 20 immediately before the ends 21, 22 are provided with reinforcements 23 which separate the ends of the film hinge 6, 7 from the ends 21, 22.

This type of hinge has the property that when raising or folding up the closure cap 1 the elastic restoring forces in the hinge initially tend to move the cap back into its closed state, however after going beyond a dead-point the elastic forces transform into a force working in the opening direction so that the cap 1 is then retained in the open condition.

As can readily be seen from FIGS. 1, 2, 6 and 8, which show side views and axial cross sections through the snap hinge 5, when the cap 1 is raised in the direction of arrow A in FIG. 8, the top plate 1 and the cap skirt 2, which in the region of the hinge 20 are formed by the curved section 16, form a relatively rigid unit. The pivotal axis for the cap initially lies close to the neck of the web 8. As can be seen from FIG. 8, on lifting the cap 1, the central section of the hinge 20 or the web 8 moves radially inwardly and is thus compressed while the outer rim section or ends 21, 22 of the hinge 20 moves radially outwardly and is thus stretched, producing the elastic restoring forces. The dead-point is defined so that the web 8 passes through the plane in the centre of the hinge in the radial direction extending between the two hinge ends 21, 22 and then snaps radially inwardly while the ends 21, 22 of the hinge 20 move radially outwardly so that the web 18 and the ends 21, 22 in the view of FIGS. 6 and 8 lie over one another and finally pass each other and on the other side of the dead-point exert an elastic force which pulls the cap into the open position.

This should ensure that liquid can be poured from a bottle without having to hold the cap away from the opening, so that the liquid pouring out does not flow against the cap and be diverted in an uncontrolled manner and thus spilled.

In the external top view of FIGS. 1, 2 and 3, the profile or contours of the tear strip 4 can be seen in detail. In the region bordering the ends 21, 22 of the snap hinge 20 in the axial direction, the tear strip 4 is widened by the width of the cap skirt 2 and extends with its enlargements 5 in this region up to the top plate 14 and thus after separating from the closure completely frees the ends 21, 22 of the snap hinge 20.

Clearly, the hinge and tear strip can equally be at a larger distance from the top plate and then the cap skirt does not have to have any corresponding recesses 25.

A particular feature of the closure shown in the Figures is that before its first use, i.e. in the state shown in FIGS. 1 to 8, it is closed on all sides. As can be seen, the cap 1, the tear strip 4 and the retaining ring 3 are connected by tearable lines 15, 19 which are formed by linear or strip shaped film-like thinned sections of the closure material. A further tearable line which is also formed by a thin film-like material runs along the ends 21, 22 of the hinge 20. On removing the tear strip, the tab grip 13 is gripped and the (not shown here) easily tearable bridges or webs which connect the tab grip 13 with the outside of the snap hinge 20 are torn off. A sufficiently powerful tug on the tab grip 13 then tears the closure material along the line 22 which defines one end of the snap hinge to which the widened end of the tear strip 4 provided with the tab grip 13 is connected. Tugging on the tab grip 13 then tears the tearable lines 15, 19 to the enlargement 5 of the tear strip 4 which connects to the end 21 of the snap hinge 20. Finally, the tearable line along the end 21 is ripped off. Thus, the tear strip has been completely separated from the closure and the cap 1 and retaining ring 3 are almost completely separated from each other and are only connected via the snap hinge 20.

In the unopened form shown in FIGS. 1 to 3, however, the closure is closed on all sides and even the retaining ring 3, when it grips behind the projection 32 of the bottle neck, preferably engages with this projection 32 and preferably also reaches the lower bottle rim 31 so that the interior of the closure, at least above the grip of the retaining ring 3 with the flange or projection 32, is at least dust tight to the exterior.

The tear strip 4 also lies close to the flange 32 of the bottle neck 30 so that the thin film of the tearable line 19 can, if appropriate, also be replaced by a gap which is bridged simply by individual easily tearable webs between the tear strip and retaining ring, without compromising the dust seal on the outer flange 32.

In an embodiment which is not shown, the tear strip on the side opposite the snap hinge 20 is widened in the axial direction to the height of the cap skirt and in this part reaches to the top plate 14 so that after removing the tear strip in this region, the cap skirt 2 also has a recess which effectively provides a gripping lip as in this region the top plate 14 is free and can be gripped at its free edge. This renders operation of the closure easier as the cap 1, as already mentioned, has one or more bead-like projections on the inner side of the cap skirt 2 which grip behind an outwardly projecting bottle neck rim and thus set up a certain resistance to opening of the cap 1.

In the preferred embodiment shown in the Figures, however, a tab grip 11 is formed outside on the cap skirt 2.

As can be seen in FIG. 6 and in particular in the detailed view of FIG. 7, at its lower rim the cap skirt 2 has a radially inward projection or snap rim 12 which grips behind a corresponding outwardly projecting projection or snap rim 33 at the upper rim of the bottle neck 30. This projection 12 extends, as can be seen in FIG. 4, over a relatively small circumferential sector of less than 60°, with its centre diametrically opposing the centre of the snap hinge 20. The circumferential sector over which the snap rim 12 extends can, however, also be substantially larger, for example 160° up to 270°, whereupon however the radial thickness of the snap rim, particularly in the regions which are at about 90° to the centre of the snap hinge, should be substantially smaller than in the region diametrically opposite the snap hinge. In particular, this snap rim or bead 12 has its largest radial thickness in the central region diametrically opposite to the snap hinge. In the circumferential region further from this central region, in particular in the circumferential sections about 90° to 120° from the central region, the bead 12 has a substantially smaller thickness and may even disappear completely. This is clearly seen in the cross section of the embodiment of FIGS. 2 a and 9 which show a section or corresponding detail E along a plane D-D, which is at 90° to the centre of the snap hinge. As can be seen, no snap rim can be seen on the cap skirt 2 in this region.

Advantageously, the radial thickness of the bead 12 tapers either in a stepwise manner or continuously away from the centre opposite the snap hinge 20. As an example, the profile of the radial thickness of the projection 12 may have a similar sickle shape to that shown in the axial view of FIG. 2, but dimensionally adjusted, rather like that of the gripping projection 11, although this projection or bead 12 extends radially inwardly, in contrast to the tab grip 11.

Clearly, other profiles and shapes for the snap rim or bead 12 can be envisaged, such as that shown in FIG. 4, where the ends of a bead 12 thin from a constant thickness in a rounded inclined step and blend into the wall of the cap skirt.

In the unopened state, i.e. while the tear strip 4 is still intact and connected with the retaining ring 3 and the cap 1, the closure is completely closed on its outer side and between the tear strip 4 on the one hand and the retaining ring or cap skirt 2 on the other hand there are no gaps, openings or slits through which any contaminants could gain ingress.

Thus, no contaminants can gain ingress into the closure which is formed by the retaining ring 3, tear strip 4 and closure cap 1. After removing the tear strip 4, the container contents are still sealed properly since as the ring-shaped circumferential sealing web 18 has a corresponding outer bead which seals against the inner surface of a bottle neck, while the cap skirt 2 with its inwardly projecting projection 12 holds the closure cap 1 securely by its lower inner edge on the container mouth.

The closure of the invention is characterized by a relatively simple structure and manner of manufacture and, in particular in the form illustrated in FIGS. 1 to 9, can be manufactured in the closed form. Further, it requires only a little material since the essential parts, namely the retaining ring, tear strip and cap or cap skirt can be made very short in the axial direction so that for a closure diameter of 38 mm, the height is not more than 12 mm, for example, of which 4.5 mm of the height is used up by the retaining ring and the cap skirt (including the top plate), and the remaining part is used up by the tear strip which in principal could be made even narrower, however the snap hinge also requires a certain axial height so that a further reduction in the width or axial height of the tear strip has no substantial further influence on the overall height of the closure. The saving on material brought about by this axially short construction is even more advantageous because a shorter bottle neck can be employed. 

1. A closure (10) consisting of a cap portion (1), a retaining ring (3), a tear strip and a snap hinge (20), the snap hinge connecting the cap portion and the retaining ring with one another in a single piece along a first circumferential section, wherein the cap portion (1) has a top plate (14) and the closure having overall a substantially cylindrical or slightly tapered closure skirt which, inter alia, comprises a substantially cylindrical cap skirt and the retaining ring (3), wherein the snap hinge (20) is integrated into the skirt and wherein the retaining ring (3) and the cap portion (1), in addition to being connected via the snap hinge (20), are also connected together along a second circumferential section (30) via the tear strip (4) which is also integrated into the skirt, characterized in that the cap skirt, tear strip, snap hinge and retaining ring together define an essentially closed closure skirt, wherein the tear strip and the ends of the snap hinge (20) in the circumferential direction are connected with the cap skirt and/or the retaining ring and optionally with one another via film-like, easily tearable lines of weakness.
 2. A closure according to claim 1, characterized in that the tear strip connects to both of the circumferential ends (21, 22) of the snap hinge (20) and extends over the entire remaining circumferential section of the closure skirt apart from the snap hinge.
 3. A closure according to claim 1 or claim 2, characterized in that the tear strip with its end sections (5) bordering the snap hinge extends substantially to the upper rim of the snap hinge and preferably over its entire axial height.
 4. A closure according to one of claims 1 to 2, characterized in that the axial height of the tear strip is smaller than that of the snap hinge with the exception of its end sections bordering the snap hinge.
 5. A closure according to one of claims 1 to 2, characterized in that a tab grip of the tear strip which starts from one end section of the tear strip extends radially from the closure skirt and in the circumferential direction over the snap hinge and is retained close to the closure skirt by easily tearable tabs, preferably in the region of the snap hinge.
 6. A closure according to one of claims 1 to 2, characterized in that the upper rim of the tear strip runs near to the top plate (14) in the region thereof opposite to the snap hinge.
 7. A closure according to one of claims 1 to 2, characterized in that the snap hinge or a film hinge (6) of the snap hinge (20) is less than 2 mm, preferably less than 1 mm distant from the top plate (14).
 8. A closure according to one of claims 1 to 2, characterized in that in the cap skirt a recess (25) is provided on both sides of the snap hinge (20) which extends almost to the top plate, and is occupied by the end sections (5) of the tear strip.
 9. A closure according to one of claims 1 to 2, characterized in that a recess is provided in the cap skirt which extends almost to the top plate diametrically opposite to the snap hinge which, on the intact closure, is filled by the tear strip.
 10. A closure according to claim 9, characterized in that the recess diametrically opposite to the snap hinge extends over an angle between 20° and 60°, preferably between 30° and 40°.
 11. A closure according to claim 8, characterized in that the recesses (25) either side of the snap hinge extend over an angle between 5° and 20°, preferably between 7° and 15°.
 12. A closure according to claim 8, characterized in that the height of the cap skirt (1) measured in the axial direction in the region of at least one of the recesses (25) is reduced by at least half, preferably by at least 75% of the height of the regions outside the recesses and in particular to a distance of less than 1 mm from the inner surface of the top plate.
 13. A closure cap according to one of claims 1 to 2, characterized in that the snap hinge is formed from a sector of a substantially cylindrical or slightly tapered skirt between the top plate (14) and retaining ring (3), wherein said sector has two film hinges (6, 7) which are formed at an axial distance from each other by essentially circumferential lines of weakness and which, starting from a minimum axial separation approximately in the centre of the hinge sector, diverge towards the ends (21, 22) of the hinge (20) bordering the tear strip.
 14. A closure cap according to claim 12, characterized in that the lines of weakness (6, 7) are each in the form of an approximately circular or elliptical curve, the centres of which lie axially above or below the snap hinge (20).
 15. A closure according to one of claims 1 to 2, characterized in that the structures on the closure skirt and between the skirt sections have a radially shallow depth of less than 2 mm, preferably less than 1 mm.
 16. A closure according to one of claims 1 to 2, characterized in that the tear strip (4), over the major portion of the second circumferential sector apart from the snap hinge (20), is at a distance from the top plate which is at least double that distance in the sectors which are close to the top plate.
 17. A closure according to one of claims 1 to 2, characterized in that the distance of the tear strip from the top plate (14) in the sectors close to the top plate is at most 1 mm and outside these sectors is at least 2 mm.
 18. A closure according to one of claims 1 to 2, characterized in that the overall axial height of the closure is less than 15 mm, preferably at most 12 mm whereby, apart from the recesses, more than a third is taken up by the retaining ring and the cap skirt and somewhat less than a third is taken up by the tear strip.
 19. A closure cap according to one of claims 1 to 2, characterized in that in the region outside the recesses the cap skirt has an inwardly projecting retaining bead (12).
 20. A closure cap according to claim 19, characterized in that the radial thickness of the retaining bead in the regions furthest from the snap hinge is larger than that in a circumferential sector of approximately 180° centred on the snap hinge.
 21. A closure cap according to claim 20, characterized in that the maximum radial thickness of the retaining bead in the regions offset from the snap hinge by more than 90° is more than twice the radial thickness thereof in the 180° sector about the snap hinge.
 22. A closure cap according to claim 20, characterized in that the retaining bead has a radial thickness which, from a maximum value in the regions offset from the snap hinge by more than 90°, reduces in the direction of the retaining hinge continuously or stepwise to a minimum value which lies between a zero thickness and at most half the maximum thickness.
 23. A closure cap according to one of claims 1 to 2, characterized in that a tab grip which is connected with one end of the tear strip (4) extends parallel to the cylindrical cap skirt along the outside of the snap hinge (20) and is connected therewith via easily tearable connecting bridges.
 24. A closure cap according to one of claims 1 to 2, characterized in that a ring-shaped sealing web (18) extends from the top plate radially inwardly of the cap skirt (10).
 25. A closure cap according to claim 24, characterized in that the outside of the sealing web (18) carries a ring-shaped circumferential bead-like radial enlargement.
 26. A closure cap according to one of claims 1 to 2, characterized in that on its inner side and in the proximity of its lower rim the retaining ring (3) has an inwardly projecting retaining bead (9) or tapers downwardly. 